Special Focus: Fire Detection in 2022

Combination of Traditional ­Ionizing or Optical Smoke Detectors and Other Types will Ensure Safety

With all types of heat, smoke and flame detectors, regardless of the techniques they employ, it is the difference to what is a ‘normal’ situation that causes them to raise the alarm. The choice of detector to be installed therefore depends on what is going to be ‘normal’ and what difference can be expected when a fire is starting. In many cases, one type alone will not be sufficient and a combination of traditional ionizing or optical smoke detectors and other types will ensure safety. Certain situations, however, preclude the use of the most common types of detector with, basically, nowhere to mount them. Take, for example, a recycling center. A very high temperature nest caused perhaps by a damaged battery could be undetected under a pile of material for a very long time before actually igniting.

Suppliers for infrared monitoring and early fire detection

Just such a problem is detected by the Waste-Scan infrared monitoring system for early fire detection by InfraTec. In each camera housing are two cameras, one infrared and one visual, as a twin system. Pan-tilt heads and are used to monitor the area and images of both channels are superimposed, which ensures excellent orientation and early fire detection. Patol offer infrared transit heat sensors to monitor waste or other material that is traveling along conveyor systems as part of their comprehensive solutions.

Options to Connect Detectors to an Alarm System: A Power and ­Signal-Carrying Cable

Detecting a fire is good; raising the alarm is better, so connecting the detectors back to an alarm panel or other centralized equipment — or even an app — will get the message through. The two options are either via a power and signal-carrying cable or via some sort of wireless link such as wireless LAN, a license-free frequency or even Bluetooth. The choice of which method to use will depend upon the local topology; the longest distance to be covered, the number of rooms/areas/buildings and the practicality of running cables at all.

Fire-Resistant and Flame-Retardant with Emission Rating to Ensure ­Minimum Possible Emissions of Smoke and Toxic Gases

It should go without saying that cable must be of a specially approved fire-resistant and flame-retardant type such as LSZH and comply with local standards and regulations for such installations. These may include a fire-survival rating (PH30, PH60 or PH120, for example), an operational rating in conjunction with the control equipment (BS8434-2 and BS8519 in the UK) as well as an emissions rating to ensure that the minimum possible smoke and toxic gases are emitted if the cable finally burns.

Suppliers for fir-resistant cables

Tratos is a respected manufacturer of such cables, with a wide range that covers every application scenario. They will also manufacture custom-designed cables if required. The Chinese cable manufacturer ZW Cables has a very informative website explaining their flame retardant and fire-resistant wire and cable products. Based in Dubai, fire-rated cable of various types are part of the broader Naffco fire-fighting product range.

Wireless Connection for Fire ­Detectors: Bluetooth for Short Ranges, WLAN for Longer Ranges

If a radio solution is preferred, perhaps because of there being no physical method of installing cable or to protect a building’s interior decoration, then the first consideration as to the type of radio is the required range. Bluetooth-based systems have the shortest range - within buildings, a maximum of around 10 meters (30 feet). This makes them primarily suitable for a domestic environment, and there are dozens of suppliers worldwide of such devices for use in private homes or very small commercial properties with a clean-air environment.

A wireless LAN solution will have a considerably longer range, but will require an absolutely reliable network with bandwidth always available i.e. not shared with other potentially bandwidth-hungry devices. During installation, each detector is enrolled into the WLAN and, if it is of the networked type, it will recognize its ‘neighbors’ to form a star or mesh network that will pass on alarms from one to the next and to the central fire alarm panel.

Frequencies for Smoke and Fire Detector Systems

Some smoke and fire detector systems use the license-free frequencies that are available in that particular country. These are not standardized worldwide at all; for example, in Germany, the bands around 434 and 868 MHz are free for short-range devices. There is of course no guarantee that a particular frequency in not already occupied by another nearby device, so it is helpful to have the installation options of using an alternative adjacent frequency.

Suppliers for wireless smoke detectors

Abus have three such wireless smoke detector products in their range, along with central control panels into which they can be integrated. The Siemens Swing series simultaneously uses two frequency bands to build a mesh of detectors, call points and the central control panel. For more extensive premises, you may prefer the products of Panasonic where there can be up to 4 base stations on each loop and up to 16 wireless units assigned to each base station.

Essential Standards and Regulations for Smoke Detectors

In all cases, it is essential to check that the chosen solution complies with local regulations. These can include, amongst others, NFPA and UL 217 standards in America, BS5839 in the UK, EN54 and/or EN14604:2005 in Europe (and VdS in Germany), or AS 3786:2014 in Australia for example. Other minimum standards will apply in other countries so always check with the local fire prevention authorities. A final essential point to observe: wireless detectors run on batteries, so as soon as you put this issue of GIT SECURITY down, make a recurring diary entry to check and/or replace those batteries annually, even if the manufacturer says that they last longer!